Thanks for your response,
We have used MarkedUp analytics for Bug & Crash reports. There we are getting exception for related to advertisement. And there is no crash count at all.
Regarding Windows Phone Emulator, Yes. We have used Emulator Windows Phone 8.1 WVGA 4 inch 512 MB.
I've been through some documentation on net, and I found there is an bug in Windows Phone 8.1 OS. So I'm just afraid will it be the reason for crashing.
Please have a look at the trace logger
https://onedrive.live.com/redir?resid=B57E8745FB049D86!1565&authkey=!AD4n0PxJiACfG6U&v=3&ithint=photo%2cpng
Thanks
hibrise